Magnetic levitation trains with vehicles of this type are driven, for example, by long-stator linear motors and have three-phase a.c. windings, which are intended to drive the vehicles and are installed along the track in a long stator. The energizing field of the linear motors is generated by carrier magnets, which act as exciting magnets at the same time, are arranged in the vehicle and form a first magnet array (e.g., DE 39 17 058 C2). The linear motors may be used not only to drive but also to brake the vehicles.
The magnetic levitation vehicles of the class described in the introduction preferably also have, on both sides, a second magnet array each, which is used for the “guiding” function and has a plurality of magnet poles arranged one after another in the direction of travel and windings associated with said magnet poles (e.g., DE 10 2004 056 438 A1). These are operated with current such that all the magnet poles that are located in a row or plane parallel to the direction of travel have the same polarity. In addition, these magnet arrays are controlled by means of control circuits and associated gap sensors such that gaps, hereinafter called guide gaps, are always maintained at equal values between the magnet poles and ferromagnetic lateral guide rails arranged on both sides at the track.
Since there is no possibility of braking any longer, e.g., in case of failure of individual or all carrier and exciting magnets or of the drive system, magnetic levitation vehicles intended for high velocities are additionally equipped with a so-called “safe” brake, which preferably comprises an eddy current brake (DE 10 2004 013 994 A1). Such an eddy current brake is formed from a third magnet array, which is arranged between the magnet arrays for the “guiding” function. This third magnet array cooperates with an electrically conductive reaction rail, preferably with the lateral guide rail, and has a plurality of magnet poles, which are arranged one after another in the direction of travel and are operated, contrary to the guiding magnet array, with different polarities, preferably alternatingly with north and south poles. Eddy currents, which brake the magnetic levitation vehicle more or less strongly as a function of the velocity of the magnetic levitation vehicle and the value of the direct current that is sent through the windings of the braking magnet array, are generated hereby in the reaction rail in case of braking.
Two problems arise, in particular, based on the described construction of usual magnetic levitation vehicles. On the one hand, the design effort associated with the three different magnet arrays is undesirably great and cost-intensive. On the other hand, the alternating arrangement of guiding and braking magnet arrays one after another along the lateral guide rails leads to a large number of load alternations, so that the forces will be introduced nonuniformly, which must be compensated by correspondingly stronger vehicle and track constructions.